diff options
Diffstat (limited to 'kernel/trace/ftrace.c')
-rw-r--r-- | kernel/trace/ftrace.c | 30 |
1 files changed, 16 insertions, 14 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 83783579378f..d9062f5cc0c0 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c | |||
@@ -27,6 +27,7 @@ | |||
27 | #include <linux/ctype.h> | 27 | #include <linux/ctype.h> |
28 | #include <linux/list.h> | 28 | #include <linux/list.h> |
29 | #include <linux/hash.h> | 29 | #include <linux/hash.h> |
30 | #include <linux/rcupdate.h> | ||
30 | 31 | ||
31 | #include <trace/events/sched.h> | 32 | #include <trace/events/sched.h> |
32 | 33 | ||
@@ -84,22 +85,22 @@ ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub; | |||
84 | ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub; | 85 | ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub; |
85 | ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub; | 86 | ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub; |
86 | 87 | ||
87 | #ifdef CONFIG_FUNCTION_GRAPH_TRACER | 88 | /* |
88 | static int ftrace_set_func(unsigned long *array, int *idx, char *buffer); | 89 | * Traverse the ftrace_list, invoking all entries. The reason that we |
89 | #endif | 90 | * can use rcu_dereference_raw() is that elements removed from this list |
90 | 91 | * are simply leaked, so there is no need to interact with a grace-period | |
92 | * mechanism. The rcu_dereference_raw() calls are needed to handle | ||
93 | * concurrent insertions into the ftrace_list. | ||
94 | * | ||
95 | * Silly Alpha and silly pointer-speculation compiler optimizations! | ||
96 | */ | ||
91 | static void ftrace_list_func(unsigned long ip, unsigned long parent_ip) | 97 | static void ftrace_list_func(unsigned long ip, unsigned long parent_ip) |
92 | { | 98 | { |
93 | struct ftrace_ops *op = ftrace_list; | 99 | struct ftrace_ops *op = rcu_dereference_raw(ftrace_list); /*see above*/ |
94 | |||
95 | /* in case someone actually ports this to alpha! */ | ||
96 | read_barrier_depends(); | ||
97 | 100 | ||
98 | while (op != &ftrace_list_end) { | 101 | while (op != &ftrace_list_end) { |
99 | /* silly alpha */ | ||
100 | read_barrier_depends(); | ||
101 | op->func(ip, parent_ip); | 102 | op->func(ip, parent_ip); |
102 | op = op->next; | 103 | op = rcu_dereference_raw(op->next); /*see above*/ |
103 | }; | 104 | }; |
104 | } | 105 | } |
105 | 106 | ||
@@ -154,8 +155,7 @@ static int __register_ftrace_function(struct ftrace_ops *ops) | |||
154 | * the ops->next pointer is valid before another CPU sees | 155 | * the ops->next pointer is valid before another CPU sees |
155 | * the ops pointer included into the ftrace_list. | 156 | * the ops pointer included into the ftrace_list. |
156 | */ | 157 | */ |
157 | smp_wmb(); | 158 | rcu_assign_pointer(ftrace_list, ops); |
158 | ftrace_list = ops; | ||
159 | 159 | ||
160 | if (ftrace_enabled) { | 160 | if (ftrace_enabled) { |
161 | ftrace_func_t func; | 161 | ftrace_func_t func; |
@@ -2276,6 +2276,8 @@ __setup("ftrace_filter=", set_ftrace_filter); | |||
2276 | 2276 | ||
2277 | #ifdef CONFIG_FUNCTION_GRAPH_TRACER | 2277 | #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
2278 | static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata; | 2278 | static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata; |
2279 | static int ftrace_set_func(unsigned long *array, int *idx, char *buffer); | ||
2280 | |||
2279 | static int __init set_graph_function(char *str) | 2281 | static int __init set_graph_function(char *str) |
2280 | { | 2282 | { |
2281 | strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE); | 2283 | strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE); |
@@ -3351,6 +3353,7 @@ void ftrace_graph_init_task(struct task_struct *t) | |||
3351 | { | 3353 | { |
3352 | /* Make sure we do not use the parent ret_stack */ | 3354 | /* Make sure we do not use the parent ret_stack */ |
3353 | t->ret_stack = NULL; | 3355 | t->ret_stack = NULL; |
3356 | t->curr_ret_stack = -1; | ||
3354 | 3357 | ||
3355 | if (ftrace_graph_active) { | 3358 | if (ftrace_graph_active) { |
3356 | struct ftrace_ret_stack *ret_stack; | 3359 | struct ftrace_ret_stack *ret_stack; |
@@ -3360,7 +3363,6 @@ void ftrace_graph_init_task(struct task_struct *t) | |||
3360 | GFP_KERNEL); | 3363 | GFP_KERNEL); |
3361 | if (!ret_stack) | 3364 | if (!ret_stack) |
3362 | return; | 3365 | return; |
3363 | t->curr_ret_stack = -1; | ||
3364 | atomic_set(&t->tracing_graph_pause, 0); | 3366 | atomic_set(&t->tracing_graph_pause, 0); |
3365 | atomic_set(&t->trace_overrun, 0); | 3367 | atomic_set(&t->trace_overrun, 0); |
3366 | t->ftrace_timestamp = 0; | 3368 | t->ftrace_timestamp = 0; |